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I've had a brick-walled cupboard removed from my kitchen, but the concrete shelf that was in it had to be left because of the gas piping around it.

The piping will be removed for 2 days soon while a new boiler is fitted and I'd like to remove the shelf with minimal damage to the walls supporting it.

I was considering an angle grinder with a concrete cutting blade, but was worried about how it would cope with the wire reinforcement? Other than that, what options do I have? Thickness of the shelf

Wire reinforcement

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I don't like using an angle grinder for deep cuts. Pinch the cutting wheel, and the wheel shatters. If you go this route, face shield, dust mask, gloves and long sleeves.

Most concrete saws I've seen run wet. If you do this, then use a GFCI circuit for your tools (and test the GFCI...) Wet means a bigger local mess, but you don't have concrete dust throughout your house.

I would see if I can find a cutting wheel that would fit a circular saw. This allows you to get within 1.25" of the edge, with some larger uncut bits in the corner. Do the back edge first. Then support the front edge. Do the right edge next. It's awkward as you need to come OUT with the saw (unless it has a left handed base plate) Given the thickness of your shelf, you may have to do this from the bottom too. If so, do the bottom first. a 300 pound slab o concrete falling on your head can ruin your day.

Might ask at a rental tool shop if they ahve something that does this sort of magic.

If they make concrete blades for reciprocating saws, you may be able to complete more of the cuts, but I think you will still end up about an inch from the wall.

Now a few whacks with a sledge should bring it down.

At this point you have a 1.25 inch stub and a ragged corner. You can see where the reinforcing runs now, so set the depth to 1.4 inches and cut into the face you just made above and below the reinforcing. This gives you a narrow ledge with no reinforcing with the base of the cut a bit deeper into the wall. If you can, extend this cut into the corner.

using a stone cutter's chisel (brick chisel) whack the corner where the shelf meets the wall. I'd try doing several passes, along the full length of shelf, the idea that you want a crack started that will break cleanly. Eventually it should crack off. With the slightly deeper cut, the break should be under the wall plane, so that you can patch rather then grinding down a rough break.

For the layer with the reinforcing, your angle grinder may shine. This is likely a fairly thin layer to blade pinching is less likely.

The bottom layer will be a very awkward swing for hammer and chisel. Perhaps a 1/8" groove cut with the angle grinder, then whack from the top.

Note: I am not a mason or a concrete worker. Advice worth what you have paid for it.

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Your plan to use an angle grinder is the way to go. The masonry disks for your grinder will cut the metal reenforcement wire or rebar. The metal will reduce the blade or disk life so get more than you think you need you can return unused ones. Cutting concrete is really messy when done dry, make sure to have a quality dust mask and you may want to seal off the room, I have gotten in trouble with the wife many times for the dust, but an angle grinder is the way to do this job. Note if you only have a 4” make the first cut on the bottom then the top cut even if not fully cut a sharp blow with a 2lb or 3lb hammer is usually enough to sheer it clean, then use the grinder to even it up. With a 9” it should make it from the top.

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A angle grinder with a concrete blade will be pretty awkward. I would use a circular saw with the concrete blade. It will cut the metal reinforcement wires too. You'll still have a lip that the circular saw can't get to so then use the angle grinder with the concrete blade or just cold chisel and hammer it out.

  • A saw would not allow you to get close to the wall. I use masonary blades all the time to do this exact job. With 4” & 9” grinders. – Ed Beal Aug 3 at 14:44
  • It would leave a lip of about 1.5 inches getting the bulk of the shelf out of the way... just my humble opinion and the way I've done it once or twice. – JACK Aug 3 at 15:27

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